Microarrow sensor array with enhanced skin adhesion for transdermal continuous monitoring of glucose and reactive oxygen species

Conventional blood sampling for glucose detection is prone to cause pain and fails to continuously record glucose fluctuations in vivo.Continuous glucose monitoring based on implantable electrodes could induce pain and potential tissue inflammation,and the presence of reactive oxygen species(ROS)due to inflammationmay affect glucose detection.Microneedle technology is less invasive,yet microneedle adhesion with skin tissue is limited.In this work,we developed a microarrow sensor array(MASA),which provided enhanced skin surface adhesion and enabled simultaneous detection of glucose and H_(2)O_(2)(representative of ROS)in interstitial fluid in vivo.The microarrows fabricated via laser micromachining were modified with functional coating and integrated into a patch of a three-dimensional(3D)microneedle array.Due to the arrow tip mechanically interlocking with the tissue,the microarrow array could better adhere to the skin surface after penetration into skin.The MASA was demonstrated to provide continuous in vivo monitoring of glucose and H_(2)O_(2) concentrations,with the detection of H_(2)O_(2) providing a valuable reference for assessing the inflammation state.Finally,the MASA was integrated into a monitoring system using custom circuitry.This work provides a promising tool for the stable and reliable monitoring of blood glucose in diabetic patients.

A CuNi/C Nanosheet Array Based on a Metal–Organic Framework Derivate as a Supersensitive Non-Enzymatic Glucose Sensor

Bimetal catalysts are good alternatives for nonenzymatic glucose sensors owing to their low cost, high activity, good conductivity, and ease of fabrication. In the present study, a self-supported CuNi/C electrode prepared by electrodepositing Cu nanoparticles on a Ni-based metal–organic framework(MOF) derivate was used as a non-enzymatic glucose sensor. The porous construction and carbon scaffold inherited from the Ni-MOF guarantee good kinetics of the electrode process in electrochemical glucose detection. Furthermore, Cu nanoparticles disturb the array structure of MOF derived films and evidently enhance their electrochemical performances in glucose detection. Electrochemical measurements indicate that the CuNi/C electrode possesses a high sensitivity of17.12 mA mM^(-1) cm^(-2), a low detection limit of 66.67 nM,and a wider linearity range from 0.20 to 2.72 mM. Additionally, the electrode exhibits good reusability, reproducibility, and stability, thereby catering to the practical use of glucose sensors. Similar values of glucose concentrations in human blood serum samples are detected with our electrode and with the method involving glucose-6-phosphate dehydrogenase; the results further demonstrate the practical feasibility of our electrode.

A novel sensitive non-enzymatic glucose sensor

Cu nanoclusters were electrochemically deposited on the film of a Nafion-solubilized multi-wall carbon nanotubes (CNTs) modified glassy carbon electrode (CNTs-GCE), which fabricated a Cu-CNTs composite sensor (Cu-CNTs-GCE) to detect glucose with non-enzyme. The linear range is 7.0 × 10?7 to 3.5 × 10?3 mol/L with a high sensitivity of 17.76 μA/(mmol L), with a low detection limit 2.1 × 10?7 mol/L, fast response time (within 5 s), good reproducibility and stability.

Non-enzymatic Glucose Sensor Based on Porous Foam Au/MXene Nanocomposites

A novel electrochemical non-enzymatic glucose sensor based on three-dimensional Au/MXene nanocomposites was developed.MXenes were prepared using the mild etched method,and the porous foam of Au nanoparticles was combined with the MXene by means of in situ synthesis.By controlling the mass of MXene in the synthesis process,porous foam with Au nanoparticles was obtained.The three-dimensional foam structure of nanoparticles was confirmed by scanning electron microscopy.Cyclic voltammetry and electrochemical impedance spectroscopy were used to study the electrochemical performance of the Au/MXene nanocomposites.The Au/MXene nanocomposites acted as a fast redox probe for nonenzymatic glucose oxidation and showed good performance,including a high sensitivity of 22.45μA·(mmol/L)^(-1)·cm^(-1)and a wide linear range of 1-12 mmol/L.Studies have shown that MXene as a catalyst-supported material is beneficial to enhance the conductivity of electrons and increase the loading rate of the catalyst materials.The foam structure with Au nanoparticles can provide a larger surface area,increase the contact area with the molecule in the catalytic reaction,and enhance the electrochemical reaction signal.In summary,this study shows that Au/MXene nanoparticles have the potential to be used in non-enzymatic glucose sensors.

Non-Enzymatic Glucose Sensor Based on the Novel Flower Like Morphology of Nickel Oxide

In this study, novel nickel oxide (NiO) flowers like nanostructures were fabricated onto gold coated glass substrate by hydrothermal method using high alkaline pH medium. The structural study of nickel oxide nanostructures was performed by scanning electron microscopy (SEM) and X-ray differaction (XRD) techniques. Nickel oxide nanostructures are highly dense, uniform and possess good crystalline quality. The so prepared structures were investigated for their electrochemical properties by cyclic voltammetry and amperometric techniques. The nickel oxide flower like morphology has shown good electrochemical performances for the oxidation of glucose. The presented sensing material was able to detected glucose in a wide range of concentration of 0.001 mM to 8 mM with a high sensitivity (123 μmA/mM) and regression coefficient of 0.99. Moreover, the NiO nanostructures based sensor is highly reproducible, stable, exhibiting a fast response time and selective in the response. All the obtained results indicate the potential use of this material in the development of enzyme free sensors for the detection of glucose.

Facile Semiconductor p-n Homojunction Nanowires with Strategic p-Type Doping Engineering Combined with Surface Reconstruction for Biosensing Applications

Photosensors with versatile functionalities have emerged as a cornerstone for breakthroughs in the future optoelectronic systems across a wide range of applications.In particular,emerging photoelectrochemical(PEC)-type devices have recently attracted extensive interest in liquid-based biosensing applications due to their natural electrolyte-assisted operating characteristics.Herein,a PEC-type photosensor was carefully designed and constructed by employing gallium nitride(GaN)p-n homojunction semiconductor nanowires on silicon,with the p-GaN segment strategically doped and then decorated with cobalt-nickel oxide(CoNiO_(x)).Essentially,the p-n homojunction configuration with facile p-doping engineering improves carrier separation efficiency and facilitates carrier transfer to the nanowire surface,while CoNiO_(x)decoration further boosts PEC reaction activity and carrier dynamics at the nanowire/electrolyte interface.Consequently,the constructed photosensor achieves a high responsivity of 247.8 mA W^(-1)while simultaneously exhibiting excellent operating stability.Strikingly,based on the remarkable stability and high responsivity of the device,a glucose sensing system was established with a demonstration of glucose level determination in real human serum.This work offers a feasible and universal approach in the pursuit of high-performance bio-related sensing applications via a rational design of PEC devices in the form of nanostructured architecture with strategic doping engineering.

Protein Templated Au-CuO Bimetallic Nanoclusters toward Neutral Glucose Sensing

In this study,the application of bovine serum albumin(BSA)as a carrier to glucose-sensitive materials for the detection of glucose was proposed.Au-Cu O bimetallic nanoclusters(Au-Cu O/BSA)were prepared using BSA as a template,the new sensing material(Au-Cu O/BSA/MWCNTs)was synthesized by mixing with multi-walled carbon nanotubes(MWCNT)and applied to non-enzymatic electrochemical sensors to detect glucose stably and effectively under neutral condition.The scanning electron microscopy was used to investigate the morphology of the synthesized nanocomposite.The electrochemical properties of the sensor were studied by cyclic voltammetry.Glucose detection experiments show that Au-Cu O/BSA/MWCNTs/Au electrode has good glucose detection ability,stability,accuracy,repeatability,and high selectivity in neutral environment.Unlike existing glucose-sensitive materials,due to the use of BSA,the composite material is firmly fixed to the electrode surface without a Nafion solution,which reduces the current blocking effect on the modified electrode.The composite materials can be effectively preserved for extremely long periods,higher than 80%activity is maintained at room temperature in a closed environment for 3 to 4 months,due to the special effects of BSA.In addition,the feasibility of using BSA in glucose-sensitive materials is confirmed.

Monte Carlo simulation based thinning and calculating method for noninvasive blood glucose sensing by near-infrared spectroscopy

Previous results show that the floating reference theory(FRT)is an effective tool to reduce the infuence of interference factors on noninvasive blood glucose sensing by near infrared spectros-copy(NIRS).It is the key to measure the floating reference point(FRP)precisely for the application of FRT.Monte Carlo(MC)simulation has been introduced to quantitatively in-vestigate the effects of positioning errors and light source drifts on measuring FRP.In this article,thinning and calculating method(TCM)is proposed to quantify the positioning error.Mean-while,the normalization process(NP)is developed to significantly reduce the error induced by light source drift.The results according to TCM show that 7 purm deviations in positioning can generate about 10.63%relative error in FRP.It is more noticeable that 1%fluctuation in light source intensity may lead to 12.21%relative errors.Gratifyingly,the proposed NP model can effectively reduce the error caused by light source drift.Therefore,the measurement system for FRPs must meet that the positioning error is less than 7 purm,and the light source drift is kept within 1%.Furthermore,an improvement for measurement system is proposed in order to take advantage of the NP model.

Promoted Non-enzymatic Glucose Sensor Based on Synergistic Effect of Hydrothermal Synthesized Ni(OH)_(2)-Graphene Nanocomposite

Although glucose electrochemical sensors based on enzymes play a dominant role in market,their stability remains a problem due to the inherent nature of enzymes.Therefore,glucose sensors that are independent on enzymes have attracted more attention for the development of stable detection devices.Here we present an enzyme-free glucose sensor based on Ni(OH)_(2)and reduced graphene oxide(rGO).The as-fabricated sensor still exhibits excellent electrocatalytic activity for detecting glucose under enzyme independent conditions.The enhanced catalytic performance may due to synergistic effect as follows:(i)the interaction between the Ni2+andπelectron of graphene induces the formation of theβ-phase Ni(OH)_(2)with higher catalytic activity;(ii)the frozen dry process works as a secondary filtration,getting rid of poorly formed Ni(OH)_(2)particles with low catalytic activity;(iii)the rGO network with good conductivity provides a good electronic pathway for promoting electron transfer to reduce the response time.Based on the synergistic effect,the sensor exhibits a wide linear detection range from 0.2µmol/L to 1.0µmol/L and a low detection limit(0.1µmol/L,S/N=3).The excellent detection performance,as well as the easy and low-cost preparation method,suggests the promising applicability of the sensor in the glucose detection market.

Highly-dispersed iron element decorated nickel foam synthesized by an acid-free and one-pot method for enzyme-free glucose sensor

The highly-dispersed iron element decorated Ni foam was prepared by simple immersion in a ferric nitrate solution at room temperature without using acid etching, and characterized by X-ray powder diffraction(XRD), scanning electron microscopy(SEM), EDAX spectrum(EDAX mapping) and Raman spectroscopy. The EDAX spectrum illustrated that iron element was highly-dispersed over the entire surface of nickel foam, and the Raman spectroscopy revealed that both Ni-O and Fe-O bonds were formed on the surface of the as-prepared electrode. Moreover, the iron element decorated Ni foam electrode can be used as non-enzymatic glucose sensor and it exhibits not only an ultra-wide linear concentration range of 1-18 mmol/L with an outstanding sensitivity of 1.0388 m A·mmol/(L·cm2), but also an excellent ability of stability and selectivity. Therefore, this work presents a simple yet effective approach to successfully modify Ni foam as non-enzymatic glucose sensor.

Large-scale manufacturing of functional single-atom ink for convenient glucose sensing

Printing techniques hold great potential in the manufacture of electronics such as sensors,micro-supercapacitors,and flexible electronics.However,developing large-scale functional conductive inks with appropriate rheological properties and active components still remains a challenge.Herein,through optimizing the formulations of ink,iron single sites supported N-doped carbon black(Fe_(1)-NC)inks can serve as both conductive electrodes and high-reactive catalysts to realize convenient glucose detection,which pronouncedly reduces the dosage of enzyme and simplifies the sensors preparation.In detail,utilizing in-situ pyrolysis method,Fe_(1)-NC single-atom catalysts(SACs)are prepared in bulk(dekagram-level).The batched Fe_(1)-NC SACs materials can be uniformly mixed with modulated ink to realize the screen printing with high resolution and uniformity.Also,the whole scalable preparation and ink-functional process can be extended to various metals(including Co,Ni,Cu,and Mn).The introduction of highly active Fe_(1)-NC sites reduces the amount of enzyme used in glucose detection by at least 50%,contributing to the cost reduction of sensors.The strategy in harnessing the SACs onto the carbon inks thus provides a broad prospect for the low-cost and large-scale printing of sensitive sensing devices.

Facile synthesis of CuO-Co_(3)O_(4)prickly-sphere-like composite for non-enzymatic glucose sensors

In the field of glucose sensors,the development of inexpensive and high-efficiency electrochemical glucose sensors is the current research hotspot.In this paper,CuO-Co_(3)O_(4)composite with a prickly-sphere-like morphology is prepared by the facile hydrothermal method for the non-enzymatic electrochemical glucose detection.X-ray diffraction,scanning electron microscopy,transmission electron microscopy,energy-dispersive X-ray spec-troscopy,and X-ray photoelectron spectroscopy are used to analyze the structure,composition,and morphology of the material.In addition,the electrochemical catalytic perfor-mance of CuO-Co_(3)O_(4)to glucose is obtained by cyclic voltammetry and chronoamperometry.The excellent elec-trochemical sensing performance may be attributed to the large number of catalytic sites in the prickly-sphere-like composite and the synergistic effect of Cu and Co.Under an applied voltage of 0.55 V,CuO-Co_(3)O_(4)composite shows sensitivity to glucose(1503.45μA·(mmol·L^(-1))^(-1)-cm^(-2)),a low detection limit(21.95μmol·L^(-1)),excellent selectivity,a high level of reproducibility,and good sta-bility.This indicates that the CuO-Co_(3)O_(4)composite has a broad prospect of non-enzymatic glucose sensing application.

Electrochemical non-enzymatic glucose sensors based on nano-composite of Co3O4 and multiwalled carbon nanotube

Nanocomposite of Co3O4 and multiwalled carbon nanotube (MCNT) was synthesised using one step solvothermal method, and an electrochemical non-enzymatic glucose sensor (Co3O4-MCNT/GCE) was successfully constructed by a dropping method. The obtained Co3O4 and Co3O4- MCNT were characterized and investigated by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Quantitative analysis of glucose was performed using the amperometric (i–t) method, and plot of current difference versus concentration of glucose was linear in the range of 1.0–122μmol/L, with a linear correlation coefficient (R^2) of 0.9983 and limit of detection (LOD) of 0.28μmol/L. Sensitivity of this sensor was evaluated as 2550μA L mmol^-1 cm^-2. This new sensor produced satisfactory reproducibility and stability and was applied to monitor trace amounts of glucose in human serum samples.

Sandwich structure confined gold as highly sensitive and stable electrochemical non-enzymatic glucose sensor with low oxidation potential

The preparation of highly sensitive and stable non-enzymatic glucose sensors is critical to the prevention and treatment of diabetes.Fe_(3)O_(4)@Au@Co Fe-LDH is prepared through a spontaneous galvanic displacement reaction.A series of structural characterizations testify the successful formation of Fe_(3)O_(4)@Au@Co FeLDH electrocatalyst,with the Au intercalating between Fe_(3)O_(4)and LDH to form the sandwich structure.Cyclic voltammetry tests indicate that Au is responsible for the electrocatalytic oxidation of glucose.The characterizations of the electrochemical sensor for glucose detection indicate that Fe_(3)O_(4)@Au@Co FeLDH possesses high sensitivity of 6342μA m M^(-1)cm^(-2),with an extremely low oxidation potential of 0.82 V vs.RHE.Even with the high glucose concentration of 15 m M,the sensitivity remains at 4359μA m M^(-1)cm^(-2).Due to the broad linear detection range(0.0375 to 15.64 m M)and the low limit of detection(12.7μM),Fe_(3)O_(4)@Au@Co Fe-LDH is applicable towards practical application.Thanks to the sandwich structure,which confines the Au in between Fe_(3)O_(4)and Co Fe-LDH,the Fe_(3)O_(4)@Au@Co Fe-LDH glucose sensor shows high long-term stability and satisfactory selectivity.The successful synthesis of the sandwichstructured Fe_(3)O_(4)@Au@Co Fe-LDH provides a new conception for the design of highly sensitive and stable non-enzymatic glucose electrodes.

脑室注射葡萄糖对翘嘴鳜摄食和糖代谢的影响

为探究鳜下丘脑葡萄糖感知系统的存在和对摄食的影响,实验以翘嘴鳜为研究对象,对鳜分别进行脑室注射生理盐水(对照组)、2-DG(葡萄糖代谢拮抗剂,100 mg/kg)和葡萄糖(10 mg/kg),探究注射后3、6和12 h不同时间点鳜摄食及糖代谢的响应机制。结果显示,脑室注射葡萄糖显著抑制鳜的摄食,而不同时间点鳜血浆葡萄糖含量无显著差异。脑室注射葡萄糖显著诱导下丘脑葡萄糖激酶基因gk(glucokinase,6 h),表明鳜下丘脑葡萄糖感知体系的存在。且脑室注射葡萄糖显著促进可卡因和苯丙胺调节转录肽基因cart(cocaine and amphetamine regulated transcript,3 h)的表达量,这可能与鳜mTOR(mammalian target of rapamycin)在下丘脑(12 h)和肝脏(6 h)中的基因表达水平的显著上调有关。另外,脑室注射葡萄糖显著诱导鳜肝脏gk(6 h)和pk(pyruvate kinase,3 h)的表达,促进糖酵解,表明脑室通过感知的葡萄糖水平促进分解代谢为机体供能。综上,本研究首次通过脑室注射葡萄糖探究鳜下丘脑葡萄糖感知系统的存在,同时发现鳜下丘脑对葡萄糖脑室注射存在响应。且脑室注射葡萄糖可能通过对gk的调控影响AMPK/mTOR通路,调控机体食欲相关基因表达进而抑制摄食。研究结果为翘嘴鳜对饲料碳水化合物的高效利用和摄食调控研究提供理论依据。

Reusable electrochemical non-enzymatic glucose sensors based on Au-inlaid nanocages

Mass detection of glucose,which is required in many applications,remains challenging.The commercial enzyme-based glucose test strips cannot be reused,and current non-enzymatic glucose sensors exhibit a narrow range of detection and slow glucose oxidation kinetics.Herein,controlled etching of Prussian blue analogue(PBA)nanocubes at the vertices is conducted and Au nanoparticles(Au NPs)are subsequently inlaid in the etched cavities by in-situ reduction of HAuCl4.The unique AuNP-PBA nanocomplexes exhibit low electrochemical potential for glucose oxidation,high electrocatalytic activity,and rapid redox electron transfer rate.Covalent immobilization of the Au-inlaid nanomaterials on a fine Au wire leads to a non-enzymatic glucose sensor with a particularly wide linear detection range(10μM to 16 mM),excellent anti-interference,and fast response.More importantly,the sensor is reusable,and its sensitivity is well maintained even after 150 times of detection.This new-concept material promises to enable high-throughput glucose detection at a low cost,which is essential in diabetic management and other healthcare applications.

Ni-Co基纳米针簇无酶葡萄糖电化学传感器性能研究

对Ni-Co基前驱体材料分别进行氧化和硫化处理,制备了尖晶石结构的NiCo_(2)O_(4)和NiCo_(2)S_(4)纳米针簇,并将合成材料作为电催化剂修饰于氧化铟锡(ITO)导电玻璃表面以构建无酶葡萄糖电化学传感电极。通过电化学表征技术,研究Ni-Co基双金属化合物的阴离子种类对其电催化氧化葡萄糖的性能影响。结果表明,基于NiCo_(2)S_(4)的传感电极具有更高的电催化活性,更快的电子转移速率。NiCo_(2)O_(4)/ITO电极在0.1~0.7 mmol/L的线性范围内灵敏度为81.8μA/(mmol/L)·cm^(2),而NiCo2S4/ITO电极的线性范围为0.1~2.0 mmol/L,且灵敏度提升至166.8μA/(mmol/L)·cm^(2)。NiCo_(2)S_(4)/ITO电极选择性、稳定性和重现性良好,在血糖检测中具有较好的应用前景。

瞬感扫描式动态葡萄糖监测仪准确性的影响因素及与血糖波动的关系

目的:探究瞬感扫描式动态葡萄糖监测系统(CGMS)准确性的影响因素及其与血糖波动的关系。方法:选取2020年9月—2022年5月于我院就诊的57例糖尿病病人为研究对象,所有病人均接受CGMS及7段指尖血糖监测,获取葡萄糖目标范围时间(TIR)及指尖血糖值,根据TIR水平将病人分为A组(TIR<70%)和B组(TIR≥70%),分析CGMS准确性的影响因素及其与血糖波动的关系。结果:A组24 h血糖高于目标范围时间(TAR)高于B组,空腹、早餐后、午餐前、午餐后、晚餐前、晚餐后、睡前的CGMS血糖值和指尖血糖也均高于B组(P<0.05);Pearson相关性分析显示,空腹、早餐后、午餐前、午餐后、晚餐前、晚餐后、睡前的CGMS血糖值和指尖血糖值均呈相关性(均P<0.05);当TIR<30%时,CGMS系统在检测午餐前血糖时的准确性最高;在30%≤TIR<50%时,CGMS系统在检测睡前血糖时准确性最高;在50%≤TIR<70%时,CGMS系统在检测晚餐后血糖时的准确性最高;在70%≤TIR≤100%时,CGMS系统在检测血糖的准确性均较高。结论:CGMS系统在糖尿病病人中的应用准确性良好,其相对平均偏差主要受病人血糖波动和测量时间的影响,当血糖波动范围为70%≤TIR≤100%时,瞬感扫描式动态血糖监测结果偏差小。

咪唑盐调控NiZn-LDH形貌以改性非酶葡萄糖传感性能

检测人体血液中的葡萄糖对糖尿病的诊断和治疗具有重要意义。通过引入不同咪唑类配体,利用一步水热法合成了一系列镍锌层状双金属氢氧化物(NiZn-LDH),探究了这些配体对NiZn-LDH形貌的影响。采用X射线粉末衍射和扫描电镜对其进行结构表征,利用电化学工作站进行电化学传感测试。2-甲基咪唑辅助合成的超薄NiZn-LDH纳米片具有葡萄糖检测灵敏度高(1708.5μA·mM^(-1)·cm^(-2))、检出限低(0.31μM)、响应时间短(小于3 s)、抗干扰和可重复性优异等特点,可用于真实血清样品中葡萄糖检测。

基于SPR效应的深刻蚀微开口双芯对称D型PCF传感器

为了进一步提升生物传感器传感性能,设计了一种基于表面等离子共振(SPR)效应的深刻蚀微开口双芯对称D型光子晶体光纤(PCF)传感器。该传感器采用堆叠、拉伸技术和化学气相沉积(CVD)技术制备,具有2种不同直径的气孔,且这2种气孔呈对称结构。介绍了采用该传感器的葡萄糖浓度检测系统原理,仿真分析了金属材料、气孔参数、抛光参数对传感器性能的影响。仿真结果表明,当折射率检测范围为1.26~1.41时,传感器的最大波长灵敏度、分辨率和葡萄糖浓度检测灵敏度分别可达24600 nm/RIU、4.06×10^(-6)RI U和2.73 nm/(g·L^(-1))。